


and i've always been this heartless

by FandomTales



Category: Life with Derek
Genre: Angst, F/M, Mild Sexual Content, Morning After
Language: English
Status: Completed
Published: 2020-10-14
Updated: 2020-11-30
Packaged: 2021-03-08 17:35:01
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 4,521
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27000559
Author URL: https://archiveofourown.org/users/FandomTales/pseuds/FandomTales
Summary: the morning after they sleep together, casey tells him it was a mistake. it doesn't break derek's heart. not even a little bit.
Relationships: Casey McDonald/Derek Venturi
Comments: 30
Kudos: 68





	1. in the morning

**Author's Note:**

> title from eden's "sex".

Derek had woken up in bed alone. In an instant he knew, even without seeing her, without speaking to her, that Casey regretted what they had done last night. He knew by the way she had made her side of the bed, with formal finality, by the way she’d left pieces of clothing on his floor, like she’d left in a hurry, and by the way she had let him sleep in. She was always bursting into his room, bright and early in the morning, dragging him out to try the coffee she had made or go on a walk with her or watch some awful daytime documentary. This morning, she hadn’t come for him. It was noon and he had just woken. He missed the way her voice dipped when she said good morning, always pretending she was apologetic. He hoped she knew she was the only one he let do that.

His knees cracked as he rolled over in bed, swinging his legs off the side of it and standing shakily. He stretched once, popping all of his joints, before he swiped a pair of pants off the floor and stepped into them. He pulled a shirt from his closet and threw it over his head. They had both seen everything, touched everything, done everything, but he didn’t know what the protocol was. He figured the more clothes the better. If she was comfortable maybe she wouldn’t panic. He was trying to search for the little optimism he had inside of himself, but something was gnawing at him, telling him to look elsewhere.

Derek could admit he slept around a lot. Casey called him a cad every time he stumbled into the apartment at 9am with rumpled clothes. He wondered if she’d call him that this morning, if he came across as the same cad to her after she saw who he was in bed.

He could hear utensils scraping in the kitchen when he stepped into the living room, so he slowly made his way there, turning these thoughts over in his head. He was trying to be quiet, but the creaky floorboard sounded off, and Casey spun around, dropping a fried egg on the floor.

“Fuck,” she said, dropping behind the counter to pick it up. That was the next hint she was regretting her actions. Casey never swore. All of her goody behavior from high school had transferred over to college. Even when they had moved into an apartment together, away from their parents and teachers and anything even authority adjacent, Casey swore only in her worst moments.

Derek knelt down next to her. In a soft voice he said, “I got it.” He shooed her away from the mess. “You’re making it worse.” 

“Yeah,” she said, voice weak as she stood up and stepped away. “I’m sorry.” 

“Don’t be.” He sidestepped her awkwardly to wash his hands.

“Derek, I’m sorry,” she said from behind him.

He scrubbed his hands under the hot water, watching his skin turn red. “You just said that.”

“Not about the eggs.”

He had been expecting it. It still hurt.

He shut the sink off when he felt sufficiently raw and clean. When he turned back around she had a plate of toast ready. She shoved it forward at him, not looking him in the eyes. She was either ashamed of herself or ashamed of him. Maybe both. He didn’t know which answer hurt the most. 

Wordlessly, Derek took the plate. She was going to explain herself in a moment regardless of what he did so he might as well eat. He bit into a piece of toast and chewed it slowly, his stomach turning too much for anything more.

“Last night,” she started, straightening up and trying to sound extra put together, the way she always did when she was drowning. “It was a mistake.”

Derek swallowed his bite but said nothing. It wasn’t that he hadn’t thought of how he might respond, it was that he didn’t trust his voice to do what it needed to do.

Whenever Derek was drowning in emotions, he shut them off. Now was the time for that.

“We were drunk,” Casey said. “We’d have never done that sober.”

“You were drunk?” 

She shook her head after a moment. “No.”

“Me neither.”

“But we were stressed, from finals, and we were making bad decisions. And you just broke up with Charlotte.”

“Charlotte and I broke up two months ago.”

Casey dropped down into the farthest stool from him, taking a deep, long drink of her coffee and staring into space. He could tell she was thinking of new ways to level with him. Derek’s eyes roamed down. She had a bruise below her jaw from him and she was pressing her fingers against it absently. 

Derek took another bite of toast. He didn’t know what to say. That it wasn’t a mistake to him? That he had wanted it, wanted it for a long time, and wanted even more? Casey was rattled, and if not completely horrified at the thought of him, completely indifferent. He couldn’t handle this.  
“You’re right,” he said. Casey looked up at him, hands gripping her coffee mug, bottom lip between her teeth. “We were tired from finals. We would never normally do this.”

“No,” Casey said, nodding to herself, “we would never have done this if we weren’t so tired.”

“Nope.”

“And it didn’t mean anything. People have casual sex all the time. You have casual sex constantly."

Constantly. Derek nods. They were just having sex. He’d never call it anything else. This was who he was and how he operated, girl to girl to girl. They meant nothing and neither did Casey.

He had one question, just something that he needed to know if they weren’t going to speak of last night after this very moment. 

“Casey, if you could take it back, would you?”

Silence followed. The faucet dripped in steady beats and Casey couldn’t hold his stare. The expression on her face was devastating. She shook her head. “Derek, I can’t- you know I can’t answer that-”

“That’s what I thought.” He stood up.

There was an ache inside him that was spilling all of his emotions overboard. He was the ship and he was the sea and he was the captain, staring out into the fog, trying not to crash onto the rocky shore. And the Siren in front of him was trying to make him do just that, like she always had. She’d been singing for so long and he was weak and tired. He wanted to lay down beside her again. Even if just to listen to her whisper his name in the dark. She had never sounded more honest than last night. He was going to miss it. One night hadn’t been enough.

She said nothing as he pulled a pair of socks and shoes on, grabbing his leather jacket from the coat rack and slipping into it. 

“Thanks for breakfast.” He took his keys from the bowl and opened the door. He paused in the doorway. “And those words I said last night? Forgot it. They meant nothing. I'm sorry if I led you on.” Casey nodded absently as Derek shut the door behind him.


	2. tasseography and the constellation andromeda

**Summary for the Chapter:**

> Casey reflects on their night together and the mistakes she made the next morning.

Derek left two hours ago. 

Casey had wanted to stop him, to grab his hand and pull him back into the apartment and tell him she messed up, that she was lying, that she was just scared. But she didn’t. And no amount of wishing could reverse the horrible moment she saw his face crumple as the door slammed shut.

She stared at the tea leaves in her mug. In freshman year, she’d taken a class in tasseography, reading tea leaves. She searched for signs now, thinking back to what they meant. These leaves told her nothing. She was on her own.

Deep down, Casey knew that what happened last night had been a long time coming. Really, it had. They’d always been something other than step siblings, something other than friends or enemies. They were in a league of their own.

Last night they’d proved that.

They’d spent the day fighting over everything. It started with a jab about an unclosed box of cereal and grew in both speed and severity until they were standing face to face in the living room, still yelling at each other, hours and hours after the sun fell.

Casey’s voice was a shrill note playing in tandem with the tv as she turned down the sounds of screaming crowds and announcers. “You’re so obnoxious! It’s like you want me to fail my finals!”

“You’re gonna fail the finals all on your own, I just want to watch the playoffs,” Derek said, snatching the remote back and turning the volume up.

Casey made a grab to get it back, stepping closer to Derek as he pulled it out of her reach. He wiggled it above their heads with a grin. Not gently, Casey stepped on Derek’s foot, knicking the remote from him as he swore. She shut the tv off completely, sliding the remote away from both of them. “All you’re doing is watching hockey!”

Derek made a noise of indignance. “Not anymore!”

“Look,” Casey snapped, fingers rubbing circles on her temples. “Can’t you just try once, not to fight with me?”

Derek scoffed. “Oh, so none of this is your fault. You’re perfect.”

“I’m glad you agree.” He shook his head at her in disbelief. 

“Yeah? How’s that B coming along in Journalism?”

Casey bristled, hackles coming up immediately. Much meaner than necessary, she snapped back. “How are you doing, Mr. Undecided Major? Got a plan yet or just want to keep wasting your money?”

“I’m figuring things out!” he said, stepping even closer, his face drawn in sharp, angry lines.

They’d fought over college and the future before. Every time they’d end up prickly and hurt, because, honestly, it stung to have this kind of shit thrown in your face, especially by someone who was there for all your freakouts and panic. But when they were in their worst moments, they couldn’t help fight over it. Now was one of those moments. 

“I think,” Casey said, ”that you don’t want anyone else to succeed and grow up, because you’d then have to.” Derek’s raised an eyebrow and Casey kept going, her head nodding as she said, “Yeah. Yeah, you don’t want to grow up because you’ll have to do adult things. You can’t cruise around on your boyish charm when you’re a grad student. You also might have to stop sleeping with every girl who looks your way.”

Derek stilled to take it all in. 

Suddenly, he was the crescendo of a wave breaking, head thrown back in laughter, hand splayed against his chest, all power and storm and fury. His breath was heaving from their fight and he couldn’t seem to catch it. Casey watched him in rapture, unsure of why she couldn’t look away. He stepped closer to her. She made out the gray in his eyes and tried not to focus on his hot breath against her jaw. 

“Now it’s my love life you’re commenting on?” he asked. “You’re gonna talk about me sleeping around? How about your serial monogamy? You’re covering up the fact that you’re scared of commitment by dating these guys. You can’t commit to them now, Casey, and you’ll never be able to.” He grinned. “You know what you want.”

His voice had been light when he spoke, but there was a fierceness behind it that proved he was serious. He hadn’t just said it to argue, to throw her own faults in her face. He’d without a doubt, thought about it before. He’d connected the dots before she had.

Casey was frozen in place with the sheer emotion bubbling up inside her. Her hands shook. If he knew, he either wanted the same as her or he wanted to ruin her. “You’re the worst,” she whispered, figuring that worked regardless of the outcome.

Derek didn’t debate. He raised an eyebrow and laughed a little. It was light and airy and slowed down with a long sigh, making her shiver. “Fuck you, Casey.”

“Fuck me yourself, coward.”

Casey’s mouth was always quicker than her brain.

They stared at each other in dead silence, white noise a rush in both their ears. 

She didn’t just say that. She closed her eyes for a second and pretended that she didn’t just say that and that she was anywhere but her living room. She thought of white sand beaches and acoustic guitars and the warm sun on her face.

She opened her eyes. Horrifyingly, she was still in their dark, tiny apartment, standing a foot away from Derek, whose eyes were wide as saucers.

It seemed, between one moment and the next, that they had both snapped back into reality with alarming clarity. Derek wasted no time closing the gap between them. He kissed her with ferocity. She kissed back, hands grabbing desperately at his shirt, teeth scraping his bottom lip. She shoved him as they kissed until the backs of his knees hit the couch and he tumbled onto the overstuffed leather. Casey broke the kiss for a moment to throw her leg over his knees, straddling him. Her hands fisted in his hair, his around her waist, tugging her to him.

“Take it off,” she said, breathing hard. She kissed him again and pulled back. “Take your shirt off.”

She leaned back to let him tug it off, tossing it behind the couch and turning back to her. He looked better than she’d imagined.

He grinned when he followed her stare. “Like what you see, Casey?”

She flushed and bit his lip hard enough to draw blood. He gasped and bucked his hips against hers.

Casey could feel Derek hardening beneath her as the minutes ran on. “We can’t go any further,” she said, pulling back from his lips. He looked confused. “We’re gonna ruin the couch,” she explained, trying to be the more responsible one even though she felt as wrecked as he looked.

Derek nodded, lips pursed. “My bedroom?”

Casey nodded sharply. 

His hands roamed down her waist, across her hips and under her, scooping her up and squeezing her ass.

“Derek!”

His laughter was joyous as he carried her to his room. She unhooked her legs from around his waist and he dropped her on the bed with a bounce, crawling in next to her.

“You okay with this?” he asked, between kisses, when his hand dropped to the button of her jeans.

Casey nodded against him, pressing her forehead to his, breathing hard. She answered with total honesty.

“I’ve been waiting a long time.” 

Casey missed everything about Derek as she replayed the night in her head. She thought back to his words after their second round, as they were panting on the bed next to each other, grinning with their hands clasped.

“You look beautiful,” he has whispered, eyes flickering across her face.

Casey had felt her cheeks heat up. “Stop-”

“I’m serious.” He lifted her hand from his chest and kissed her palm. She couldn’t tear her eyes away. It was like he was an entirely new person. “You also look super hot. Let’s not get too sappy while we’re naked.”

Okay, maybe he wasn’t an entirely new person.

He rubbed her back with his left hand, fingertips grazing across the planes of her shoulders. “How do you feel?”

Casey nodded, eyes glazed, following the line of sticker stars on his ceiling, trying to make out constellations from the haphazard arrangement he’d placed them in. “I feel amazing,” Casey said, picking out the constellation Andromeda. 

“Good.”

“How do you feel?” she asked Derek, glancing over at his serene face.

“Amazing.”

Casey hummed a joyful noise. She was drifting asleep, thinking of Andromeda, lucky Andromeda, rescued from the beast by the daring Perseus, who loved her enough to risk everything. 

She let her eyes fall shut and for the moment, everything had been warm and quiet and still. 

“Goodnight, Spacey. See you in the morning.” 

She thinks, upon reflection, that he might have kissed her forehead as she was falling asleep. 

He had kissed her when she was too scared to kiss him.

Only for her to shut him down.

She had brought his number up in her phone, staring down at it. 

Come home, she texted. We need to talk.

**Notes for the Chapter:**

> Sorry it took so long to get this chapter out! I was struggling with writing something I liked, since I hadn't planned on continuing this, but I feel pretty good with it now. I hope you all enjoyed it and it wasn't a let down from the first chapter. Thanks for the encouragement to write more <3


	3. the leap

**Summary for the Chapter:**

> Derek reads the text seven minutes after she sends it. He does not come home for seven hours.

Derek felt his phone buzz in his back pocket. He knew before reading it that it was Casey.

And when he did read it, he didn’t respond because, honestly, what the fuck was he supposed to say to that? 

Come home. We need to talk.

She called their apartment home in the text, and for a moment, Derek went a little weak and warm. He wasn’t sentimental, Casey had just worn him down. He liked their dumb little decorations and their movie nights and their morning coffee. They had built up their apartment from the bare necessities. It was lived in, there were traditions forged inside of it. He’d probably miss it, and while he was not a mind reader, he was a realist. They were going to move out. That’s why it didn’t matter if he texted her back anyway. She didn’t want to talk about what had happened; she just wanted to talk about what was going to happen.

He knew Casey. Excluding Sam, she’d cut all her ex-boyfriends out of her life as soon as they broke up. It was how she coped with the awkwardness, the pain, and the tenderness of a fresh separation. Casey didn’t press on bruises, she covered them up and looked away, moving gingerly until the worst had passed. And with their lease coming to an end, Casey was going to cover up this bruise too. 

So they’d move out. Talk less. Go back to the way things were. He’d lived with that for 6 years. He could do it again.

No doubt, Casey would also bar them from going home at the same time, lest their family grow suspicious of their strange behavior. 

He’d get Christmas break because Derekus was his thing, but she’d want Thanksgiving and Spring break. Summers would be awkward, but Derek didn’t need to go home anyway, he’d find a place with friends and deal with it. Or maybe Casey would get an internship and not need to go home. It would be fine. 

Derek felt better about everything already. It might have to do with the beer he was nursing, and the bottle already finished in front of him, but the pain was dull and sweet. He could only see Casey’s blushing face, not her sallow, regretful one. Could only feel her joy, none of her remorse. He was becoming nostalgic and removed already. That’s what Casey did. She forgot. She pressed forward. Derek was just trying to see it her way. 

Earlier, Derek had caught a bus back to Queen’s University to see his old roommate. After their first beer, his old roommate had called a few friends to come over. And then those friends called other friends. They were the loud and raucous ones Derek had been remiss to leave behind when he moved off campus. Casey would never let them into the apartment. They brought more beer, more games, and more girls.

A blonde girl sat down next to Derek, grinning at him, insincere and cheshire. She hung onto his every word and gripped his forearm when she laughed. She’d usually be Derek’s type, but when she leaned in and whispered something about living nearby, Derek hated it. He turned her down. She got up from the couch and left for the kitchen, leaving Derek alone with his beer.

“Come on, man,” one of the guys said, swatting his shoulder. “She’s a babe. She wanted you.”

“For sure,” Derek said, looking down into the neck of the bottle, watching the liquid roil and rise like a tsunami. “I’m just not interested.”

He stayed for a long while, got a little drunk, and then got a little sober. He was more or less in his right mind when the sun went down. 

“I got to go,” he said, patting his old roommate’s arm. 

“Who needs you back so soon, D-Man? You got a wife or something at home that we don’t know about?” 

“Or something,” Derek laughed. “Take care, man.”

His old roommate’s face grew a little more serious. “You too.”

Derek checked his phone when he got on the bus, sliding into a window seat and letting the city blur past him. They were a series of backlogged texts, all from Casey.

1:30: Come on, Derek. 

1:42: Please.

2:10: I’m sorry. I have to talk to you.

4:04: I fucked up, I know. 

8:09: I hope you’re okay. 

9:30: Derek.

He could hear the upwards lilt of her voice on the last one, could almost see her stomping her foot. It made him grin a little, a giddy feeling knocking around inside his chest. 

But it didn’t last.  
Because Casey was angry and he was sulking and they were making each other miserable. They’d always done this. Made each other miserable. 

Maybe, Derek thought, that in the absence of making each other feel anything else, they had to make each other feel miserable. It was the nature of their relationship. Fight. Make up. Feel things. Deny things. Always pushing too far.

He got off the bus with this thought in his head, wondering how far they were going to push each other tonight. 

He climbed the steps up to their apartment slowly. He unlocked the door and stepped in, toeing off his shoes and setting his keys in the bowl. For a moment, he thought Casey might be sleeping. Shamefully, he felt relieved. 

He made it about two more steps into the apartment before Casey walked out of her room. She looked tired.

He nodded by way of greeting.

“Where were you Derek? She looked suddenly more awake as she was striding over to poke him in the chest. He took a step back from her, feeling dejavu from the night before, when they’d been standing in each other's space like this and fighting. More than fighting. He walked around her, leaving several feet between them, a safe distance from any and all contact she could try to make. It was better this way. One bad hookup and they could salvage their relationship; two and they might never speak again.

Derek collapsed into his chair, Casey following him. She was relentless. He grabbed the remote, turning the tv on and flicking through the channels. He could feel her stare burning into him. He went through all the channels twice, her patiently waiting, and finally chose the NHL network. The mess that had started it all. He looked up at her, daring her to do something about it, feeling weak that his only defense was to fight with her, like it had always been. 

She took the remote from his hand. Their fingers brushed together as she did so and he could hear her breathing stop for a second. She took a steadying deep breath as she set the remote back on the side table.

“Derek, we need to talk.”

Just what he’d been waiting for. 

The talk. 

“When the lease is up, we don’t need to renew it. I’ll take Christmas, you take everything else. We can play summers by ear, but honestly, you’ll probably get your internship and you won’t need to go back to Nora and Dad’s-”

“Please,” she said, sounding newly choked up, face buried in her hands. Derek froze. He leaned into her just as she looked up. “Don’t tell me you want to move out because of this.”

She said it so quietly it was almost inaudible. 

Derek was clueless as always on what to say to crying girls, but his tongue was still loose from the alcohol. 

“I’m just trying to be proactive here. We made a mistake.”

“Did we?” 

His features were steel. “Yes. You said so yourself.”

She nodded a little, gaze swinging down to her hands. She laced her fingers together and set them on her lap primly. She said something completely inaudible this time.

“I didn’t get that, Case.”

She looked up at him and whispered: “I liked it.”

His heart was thudding loudly in his chest, picking up speed like a racehorse. It beat so hard that it hurt, sending blood rushing into his ears. Everything was a beautiful white noise again. He wasn’t sure if he should believe it, but she spoke again as if she could read his mind.

“I really liked it. I like you.”

She was still looking at him. It was so earnest and open he could fall apart. He hated feeling like this, but he couldn’t stop. 

They struggled to hold each other’s gaze. Derek looked down this time. He took to watching as the moon casted shadows on the floor. 

“You asked me if I would take it back if I could.”

Derek nodded. The embarrassment of the morning swelled back up inside him, wedging a tight piece of shame in his throat. He cleared it, waiting for the other shoe to drop. She liked it and she liked him but she couldn’t do it. The leap was too great. Too much space to possibly lose everything and he could understand-

“I wouldn’t.”

His head snapped up.

“I wouldn’t take it back. And I would do it again.”

“Casey-”

“I was just afraid. Derek, you know me, I play it safe.”

He laughed a little at that. She smiled, emboldened, reaching across the invisible boundary lines to take his hand.

“I want to be with you, Derek. What do you think?”

Last night, Derek had said “you look beautiful” and what he thought was you always look beautiful and this is the first time i’ve been brave enough to say it. 

This morning, Derek had said “those words meant nothing” and what he thought was if you want to throw it all away, you can. i’m not going to and i never will, but i won’t force you into this. 

Two minutes ago he said “I’m just trying to be proactive here, we made a mistake” and what he thought was casey you were the one who turned me down. let me lie to myself. stop looking at me like that. i’m gonna explode if you never kiss me again and the best thing right now is for you to leave or me to leave but we can’t keep standing here and staring at each other.

Now, Derek said “I want to be with you too.”

What he thought was “casey’s leaning in to kiss me. she’s kissing me. i’m kissing back. It’s the best thing i’ve ever done or ever will do. and i want to do it for the rest of my life.”

**Notes for the Chapter:**

> Thank you all so much for reading!! I only planned for this to be a one shot, but I had a lot of fun doing a couple more chapters, and I'm a sucker for a happy ending. I hope you enjoyed where it went!
> 
> Let me know your thoughts in the comments :)

**Author's Note:**

> leave a kudos or comment if you enjoyed :)  
> criticism always accepted.  
> thanks for reading <3


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